一种低流速气体流量传感器的研制

Development of low velocity gas flow sensor

提出一种基于温差测量原理测量低流速气体流量的方法并进行了实验验证.传感器由一对集成温度传感器芯片与片状铂电阻热源构成,专门设计的片上恒流供电电路保证了热源加热功率的稳定.对该流量传感器样品进行测试,结果表明它能够提供与方根流速近似成线性关系的输出.在低于 0.5 cm/s的低流速下,该传感器具有数十至数百毫伏的输出信号幅度,其测量下限可低至0.5 cm/s.这与理论分析结果基本相符.该流量传感器在低流速条件下具有高灵敏度和较高的稳定性.

A new flow sensor suitable for measuring low velocity gas flow was developed and tested, which works by detecting the flow-induced temperature difference. The sensor consisted of two identical temperature sensor chips together with a surface-mounted precise platinum resistor that works as a heating resource. An integrated constant current source was designed to provide the heat source with a stable heating current. The output voltage of the sensor varies approximately linearly with the square root of the fluid flow velocity. The experimental results that consistent with the theoretical analysis showed that while the fluid flow velocity was as low as 0.5 cm/s, the sensor had large enough output voltages of up to several hundred millivolts. The main advantages of the flow sensor include its high sensitivity within the range of low flow velocities as well as its high stability during measurement.